Formation degradation, such as asphalt milling, mining, or excavating, may result in wear on attack tools. Consequently, many efforts have been made to efficiently remove and replace these tools.
U.S. Pat. No. 6,585,326 to Sollami, which is herein incorporated by reference for all that it contains, discloses a bit holder with its mating bit block utilizing a slight taper in the bit block bore, and a tapered shank on the bit holder that includes a second larger diameter tapered distal segment that combines with an axially oriented slot through the side wall of the bit holder shank to allow a substantially larger interference fit between the distal tapered shank segment and the bit block bore than previously known. When inserting the bit holder in the bit block bore, the distal first tapered segment resiliently collapses to allow insertion of that segment into the bit block bore. A second shank tapered portion is disclosed axially inwardly of the first distal tapered portion. The dual tapered shank allows the insertion of the bit holder in the bit block with an interference fit that provides a secure mounting of the bit holder in the bit block.
U.S. Pat. No. 6,685,273 to Sollami, which is herein incorporated by reference for all that it contains, discloses a bit assembly for road milling, mining, and trenching equipment that includes a streamlined tip assembly that is a combination of conical and cylindrical in shape and devoid of protrusions or annular indentations that might impede the flow of removed material over and around the bit assembly or provide space for removed material to become clogged or imbedded on the tip assembly. The portion of the bit block which mounts on a drum or endless chain extends from a cylindrical portion of the bit block and provides opposed angled shoulders which extend downwardly and away from a central ridge on the bit block to again provide for efficient flow of removed material over and around the bit block.
U.S. Pat. No. 3,751,115 to Proctor, which is herein incorporated by reference for all that it contains, discloses a combination of a shanked tool and a holder therefore the holder being formed with a socket for receiving the tool shank and with a resilient latch biased in a direction transverse to the operating direction for engaging in a recess in the side of the tool shank.
U.S. Pat. No. 3,468,553 to Ashby et al., which is herein incorporated by reference for all that it contains, discloses a tool retaining device having a metal locking pin bonded in a groove of a resilient backing member. One end of the backing member is formed with an integral end sealing cap and the other end has a projecting spigot onto which a further end sealing cap is fitted when the device is fitted in a tool holder. In the fitted position, the two sealing caps respectively seal the ends of the device and thereby prevent the ingress of foreign matter.
In accordance to U.S. Pat. No. 3,865,437 to Crosby, which is herein incorporated by reference for all that it contains, a mining tool of the type in which a pick style bit is rotatably mounted in a bore in a support member and is retained therein by retaining means integrally formed on the bit. The retaining means advantageously takes the form of at least one radial projection on the rear end of the bit shank with the bit shank being slotted to impart radial resilience thereto so the bit can be assembled with the support member and readily disassembled therefrom while being retained therein during work operations. The support member may comprise a support block adapted for being fixed to a driver with a sleeve rotatable in a bore in the block and in turn, rotatably receiving the bit. The sleeve may be slotted axially from the rear end so as to have later resilience and be formed with one or more radial projections or protrusions at the rear end so that the sleeve, also, is releasably retained in the block by retaining means integral therewith.
Examples of degradation tools from the prior art are disclosed in U.S. Pat. No. 2,989,295 to Prox Jr., U.S. Pat. No. 6,397,652 B1 to Sollami, U.S. Pat. No. 6,685,273 B1 to Sollami, which are all herein incorporated by reference for all they contain.